This type of display device, in which the display face is considered to be orientated upwards, includes in particular:                a liquid crystal cell comprising at least a top substrate and a bottom substrate, at least two electrodes and at least one counter-electrode which are structured on the opposite faces of the two substrates, each electrode representing a figurative pattern or a portion of a figurative pattern,        a control unit which controls the liquid crystal cell by applying a control voltage of determined value between a selected electrode and the counter-electrode so as to alter the orientation of the liquid crystals and to cause the display of the corresponding figurative patterns, and        a backlighting module, arranged under the liquid crystal cell, on the side opposite to the display face, comprising at least a first and a second light source of different colours, which transmit light rays inside at least one light guide.        
This type of display device has the advantage of being inexpensive, since the technology used for the liquid crystal cell, called the segment display, is simple and tested. It uses electrodes in the shape of segments of characters which allows a simplified electronic circuit to be used, the powering of each electrode or segment being directly controlled in an all or nothing mode, and the counter-electrode, generally in the form of a plate, being earthed. Control of this type of liquid crystal cell does not therefore require the lines and columns to be scanned, as in a matrix type display, which, in addition to simplifying the electronic control circuit, makes the display patterns easier to read.
Generally, liquid crystal segment display cells are monochrome. The display segments appear for example in black, when a reflective film is placed under the cell and said segments are powered to prevent light being reflected onto the display face. The display segments can also appear in the colour of the light source of the backlighting module.
In order to increase the display possibilities and improve aesthetic appearance, it has been proposed to make the display device multicoloured by using a backlighting module comprising several light sources of different transmission colours.
A display device of this type is disclosed in JP Patent No 3217818 A. In this document, the segment display control, character display control and light source lighting control are synchronised via a central control circuit so as to allow each segment to be successively displayed in one of the colours.
This solution is not completely satisfactory since it requires a complicated electronic control circuit to achieve synchronisation. Moreover, at any given instant, all of the displayed segments are lit with the same colour, or the same mixture of colour obtained by lighting several sources simultaneously.
It is an object of the present invention to overcome the aforecited drawbacks by proposing a display device that it simpler to manufacture and simpler to control. It is also an object of the present invention to propose a display device having an improved light output and thus improved legibility of the patterns to be displayed.